Description
Incorrect access control in the delSlaveDevice function of TOTOLINK T6 4.1.5cu.748_B20211015 allows unauthenticated attackers to remove a specified slave device from local mesh management data and reboot the system via sending a crafted MQTT message to the cs_broker component.
Published: 2026-09-01
Score: 9.8 Critical
EPSS: < 1% Very Low
KEV: No
Impact: Denial of Service
Action: Immediate Patch
AI Analysis

Impact

The vulnerability is an incorrect access control in the delSlaveDevice functionality of TOTOLINK T6 firmware 4.1.5cu.748_B20211015 that allows unauthenticated users to send a crafted MQTT message to the cs_broker component, causing the removal of a specified slave device from local mesh management data and rebooting the router. This can take devices offline and disrupt the local network.

Affected Systems

Affected systems are TOTOLINK T6 routers running firmware version 4.1.5cu.748_B20211015 or earlier that expose the cs_broker MQTT broker.

Risk and Exploitability

The flaw is exploitable without any authentication and requires only network access to the MQTT broker. EPSS score of < 1% indicates a low but nonzero exploitation probability. The CVSS score of 9.8 indicates critical severity. The vulnerability is not listed in the CISA KEV catalog, but the nature of the vulnerability—unauthenticated control of device removal and reboot—indicates it is a high‑risk, denial‑of‑service vector. Attackers could use any networked device capable of communicating with the cs_broker to trigger the exploit.

Generated by OpenCVE AI on September 3, 2026 at 16:48 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Apply the latest TOTOLINK firmware that includes the fix for the access‑control issue.
  • Restrict which devices may publish to the cs_broker MQTT topic by implementing network segmentation or firewall rules.
  • Enforce authentication on the MQTT topics for device management so only verified devices can invoke delSlaveDevice.

Generated by OpenCVE AI on September 3, 2026 at 16:48 UTC.

Tracking

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Advisories

No advisories yet.

History

Thu, 03 Sep 2026 15:15:00 +0000

Type Values Removed Values Added
Title Unauthenticated Remote Reboot and Device Removal via MQTT in TOTOLINK T6
Weaknesses CWE-285

Wed, 02 Sep 2026 21:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Wed, 02 Sep 2026 18:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-284
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

Tue, 01 Sep 2026 22:00:00 +0000

Type Values Removed Values Added
Title Unauthenticated Remote Reboot and Device Removal via MQTT in TOTOLINK T6
Weaknesses CWE-285

Tue, 01 Sep 2026 15:15:00 +0000

Type Values Removed Values Added
First Time appeared Totolink
Totolink t6
Vendors & Products Totolink
Totolink t6

Tue, 01 Sep 2026 13:45:00 +0000

Type Values Removed Values Added
Description Incorrect access control in the delSlaveDevice function of TOTOLINK T6 4.1.5cu.748_B20211015 allows unauthenticated attackers to remove a specified slave device from local mesh management data and reboot the system via sending a crafted MQTT message to the cs_broker component.
References

Subscriptions

Totolink T6
cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published:

Updated: 2026-09-02T17:44:37.127Z

Reserved: 2026-06-08T00:00:00.000Z

Link: CVE-2026-51751

cve-icon Vulnrichment

Updated: 2026-09-02T17:44:30.811Z

cve-icon NVD

Status : Deferred

Published: 2026-09-01T14:17:35.667

Modified: 2026-09-03T17:21:57.410

Link: CVE-2026-51751

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-03T17:00:06Z

Weaknesses